DOUBT has been cast on stricken midfielder Oubina's permanent transfer to Blues.

The Spaniard ruptured his anterior cruciate ligament and suffered other damage to his knee just 13 minutes into his starting debut at Liverpool.

Oubina has gone back to the club that loaned him to Blues, Celta Vigo, who had planned to sell him to for around eight millions euros at the season's end. Oubina, though, is set to be out for at least six months.

And in reality, he probably won't kick a ball in anger again this campaign because of the serious nature of the injury.

"He's torn his ACL so that, I would imagine, puts him out for the rest of the season," said coach Eric Black. "It's hard to know about what happens in the future as we speak. Not until we see what the operation has entailed and how he recovers will we have an idea.

"It's a big blow for the boy because he was making a real effort to integrate himself in the club. He was learning English and even in the first 10 minutes on Saturday you could see that he is a competent footballer."